.\"	$OpenBSD: X509_EXTENSION_set_object.3,v 1.10 2019/06/06 01:06:59 schwarze Exp $
.\"	OpenSSL bb9ad09e Jun 6 00:43:05 2016 -0400
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.Dd $Mdocdate: June 6 2019 $
.Dt X509_EXTENSION_SET_OBJECT 3
.Os
.Sh NAME
.Nm X509_EXTENSION_new ,
.Nm X509_EXTENSION_free ,
.Nm X509_EXTENSION_create_by_NID ,
.Nm X509_EXTENSION_create_by_OBJ ,
.Nm X509_EXTENSION_set_object ,
.Nm X509_EXTENSION_set_critical ,
.Nm X509_EXTENSION_set_data ,
.Nm X509_EXTENSION_get_object ,
.Nm X509_EXTENSION_get_critical ,
.Nm X509_EXTENSION_get_data
.\" In the next line, the capital "E" is not a typo.
.\" The ASN.1 structure is called "Extension", not "extension".
.Nd create, change, and inspect X.509 Extension objects
.Sh SYNOPSIS
.In openssl/x509.h
.Ft X509_EXTENSION *
.Fn X509_EXTENSION_new void
.Ft void
.Fn X509_EXTENSION_free "X509_EXTENSION *ex"
.Ft X509_EXTENSION *
.Fo X509_EXTENSION_create_by_NID
.Fa "X509_EXTENSION **ex"
.Fa "int nid"
.Fa "int crit"
.Fa "ASN1_OCTET_STRING *data"
.Fc
.Ft X509_EXTENSION *
.Fo X509_EXTENSION_create_by_OBJ
.Fa "X509_EXTENSION **ex"
.Fa "ASN1_OBJECT *obj"
.Fa "int crit"
.Fa "ASN1_OCTET_STRING *data"
.Fc
.Ft int
.Fo X509_EXTENSION_set_object
.Fa "X509_EXTENSION *ex"
.Fa "const ASN1_OBJECT *obj"
.Fc
.Ft int
.Fo X509_EXTENSION_set_critical
.Fa "X509_EXTENSION *ex"
.Fa "int crit"
.Fc
.Ft int
.Fo X509_EXTENSION_set_data
.Fa "X509_EXTENSION *ex"
.Fa "ASN1_OCTET_STRING *data"
.Fc
.Ft ASN1_OBJECT *
.Fo X509_EXTENSION_get_object
.Fa "X509_EXTENSION *ex"
.Fc
.Ft int
.Fo X509_EXTENSION_get_critical
.Fa "const X509_EXTENSION *ex"
.Fc
.Ft ASN1_OCTET_STRING *
.Fo X509_EXTENSION_get_data
.Fa "X509_EXTENSION *ne"
.Fc
.Sh DESCRIPTION
.Fn X509_EXTENSION_new
allocates and initializes an empty
.Vt X509_EXTENSION
object, representing an ASN.1
.Vt Extension
structure defined in RFC 5280 section 4.1.
It is a wrapper object around specific extension objects of different
types and stores an extension type identifier and a criticality
flag in addition to the DER-encoded form of the wrapped object.
.Vt X509_EXTENSION
objects can be used for X.509 v3 certificates inside
.Vt X509_CINF
objects and for X.509 v2 certificate revocation lists inside
.Vt X509_CRL_INFO
and
.Vt X509_REVOKED
objects.
.Pp
.Fn X509_EXTENSION_free
frees
.Fa ex
and all objects it is using.
.Pp
.Fn X509_EXTENSION_create_by_NID
creates an extension of type
.Fa nid
and criticality
.Fa crit
using data
.Fa data .
The created extension is returned and written to
.Pf * Fa ex
reusing or allocating a new extension if necessary, so
.Pf * Fa ex
should either be
.Dv NULL
or a valid
.Vt X509_EXTENSION
structure.
It must not be an uninitialised pointer.
.Pp
.Fn X509_EXTENSION_create_by_OBJ
is identical to
.Fn X509_EXTENSION_create_by_NID
except that it creates an extension using
.Fa obj
instead of a NID.
.Pp
.Fn X509_EXTENSION_set_object
sets the extension type of
.Fa ex
to
.Fa obj .
The
.Fa obj
pointer is duplicated internally so
.Fa obj
should be freed up after use.
.Pp
.Fn X509_EXTENSION_set_critical
sets the criticality of
.Fa ex
to
.Fa crit .
If
.Fa crit
is zero, the extension in non-critical, otherwise it is critical.
.Pp
.Fn X509_EXTENSION_set_data
sets the data in extension
.Fa ex
to
.Fa data .
The
.Fa data
pointer is duplicated internally.
.Pp
.Fn X509_EXTENSION_get_object
returns the extension type of
.Fa ex
as an
.Vt ASN1_OBJECT
pointer.
The returned pointer is an internal value which must not be freed up.
.Pp
.Fn X509_EXTENSION_get_critical
returns the criticality of extension
.Fa ex
it returns 1 for critical and 0 for non-critical.
.Pp
.Fn X509_EXTENSION_get_data
returns the data of extension
.Fa ex .
The returned pointer is an internal value which must not be freed up.
.Pp
These functions manipulate the contents of an extension directly.
Most applications will want to parse or encode and add an extension:
they should use the extension encode and decode functions instead
such as
.Xr X509_add1_ext_i2d 3
and
.Xr X509_get_ext_d2i 3 .
.Pp
The
.Fa data
associated with an extension is the extension encoding in an
.Vt ASN1_OCTET_STRING
structure.
.Sh RETURN VALUES
.Fn X509_EXTENSION_new ,
.Fn X509_EXTENSION_create_by_NID ,
and
.Fn X509_EXTENSION_create_by_OBJ
return an
.Vt X509_EXTENSION
pointer or
.Dv NULL
if an error occurs.
.Pp
.Fn X509_EXTENSION_set_object ,
.Fn X509_EXTENSION_set_critical ,
and
.Fn X509_EXTENSION_set_data
return 1 for success or 0 for failure.
.Pp
.Fn X509_EXTENSION_get_object
returns an
.Vt ASN1_OBJECT
pointer.
.Pp
.Fn X509_EXTENSION_get_critical
returns 0 for non-critical or 1 for critical.
.Pp
.Fn X509_EXTENSION_get_data
returns an
.Vt ASN1_OCTET_STRING
pointer.
.Sh SEE ALSO
.Xr ACCESS_DESCRIPTION_new 3 ,
.Xr AUTHORITY_KEYID_new 3 ,
.Xr BASIC_CONSTRAINTS_new 3 ,
.Xr d2i_X509_EXTENSION 3 ,
.Xr DIST_POINT_new 3 ,
.Xr ESS_SIGNING_CERT_new 3 ,
.Xr EXTENDED_KEY_USAGE_new 3 ,
.Xr GENERAL_NAME_new 3 ,
.Xr NAME_CONSTRAINTS_new 3 ,
.Xr OCSP_CRLID_new 3 ,
.Xr OCSP_SERVICELOC_new 3 ,
.Xr PKEY_USAGE_PERIOD_new 3 ,
.Xr POLICYINFO_new 3 ,
.Xr PROXY_POLICY_new 3 ,
.Xr SXNET_new 3 ,
.Xr TS_REQ_new 3 ,
.Xr X509_check_ca 3 ,
.Xr X509_check_host 3 ,
.Xr X509_check_issued 3 ,
.Xr X509V3_get_d2i 3 ,
.Xr X509v3_get_ext_by_NID 3
.Sh STANDARDS
RFC 5280: Internet X.509 Public Key Infrastructure Certificate and
Certificate Revocation List (CRL) Profile
.Sh HISTORY
.Fn X509_EXTENSION_new
and
.Fn X509_EXTENSION_free
first appeared in SSLeay 0.6.2.
.Fn X509_EXTENSION_create_by_NID ,
.Fn X509_EXTENSION_create_by_OBJ ,
.Fn X509_EXTENSION_set_object ,
.Fn X509_EXTENSION_set_critical ,
.Fn X509_EXTENSION_set_data ,
.Fn X509_EXTENSION_get_object ,
.Fn X509_EXTENSION_get_critical ,
and
.Fn X509_EXTENSION_get_data
first appeared in SSLeay 0.8.0.
These functions have been available since
.Ox 2.4 .
